Alliances have come of age. In the last ten years, they have gone from being a peripheral tool of management, used mostly to enter restricted overseas markets, to a centerpiece of corporate strategy and competitive advantage. Today, many companies have portfolios of twenty or more alliances?and some have more than a hundred. Because of this, it is now common to see alliances account for 20?50 percent of corporate value?whether measured in terms of revenues, assets, income, or market capitalization. Alliances are fueling the success of a wide range of firms, including British Petroleum, Eli Lilly, General Electric, Corning Glass, Federal Express, IBM, Starbucks, Cisco Systems, Millennium Pharmaceuticals, and Siebel Systems. As alliances moved from periphery to center of corporate strategy, the discussion surrounding them changed subtly. Executives are no longer asking ?Why do an alliance?? but rather ?How do we make our alliances succeed?? Over the years, numerous studies have shown that between 30 percent and 70 percent of alliances fail? that is, do not meet the goals of the parent companies. Whatever the number, it is clear that in many companies alliance performance lags far behind what could and should be achieved.